Fatigue/Impact Studies in Laminated Composites

Abstract

The residual strength of the impact-damaged laminates can be predicted using an analytical model. Both the power law and the wearout models appear to be useful in predicting the fatigue life of the composite laminates. However, because of the slope parameter, the wearout model appears to have a slight edge over the power law model, particularly at low fatigue life and higher applied stress. The strength degradation due to cyclic loading in notched laminates was found to be extremely small up to a million cycles. The residual strength of the fatigue-damaged laminates was found to increase (in proportion to the applied maximum stress with R = 0.1) after a million fatigue cycles. Impact loading followed by cyclic loading was found to be more damaging (in reducing the life of the laminate) than the reversed sequence of loading. The magnitude of the minimum projectile velocity causing catastrophic failure in the laminates tested was found as a function of the applied stress and the number of fatigue cycles.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1983
Accession Number
ADA142841

Entities

People

  • V. S. Avva

Organizations

  • North Carolina Agricultural and Technical State University

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force
  • Composite Materials
  • Epoxy Composites
  • Experimental Data
  • Failure Mode And Effect Analysis
  • Fatigue Tests (Mechanics)
  • Impact Loads
  • Laminates
  • Materials
  • Materials Processing
  • Mechanical Engineering
  • Mechanical Working
  • Mechanics
  • Plastic Explosives
  • Tensile Strength
  • Test And Evaluation
  • X Rays

Fields of Study

  • Materials science

Readers

  • Statistical inference.
  • Structural Health Monitoring of Composite Structures.